Minnesota Mining and Manufacturing files patent 4501923A: Process for preparing adrenochrome

A process is described for preparing adrenochrome comprising oxidizing adrenaline or a salt thereof with a persulfate in an aqueous medium at a pH in the range 4 to 8 in the presence of one or more water-soluble salts of bismuth.

— Process for preparing adrenochrome

Source:

• 
  February 26, 1985. Deryck F. Boot. Process for preparing adrenochrome. United States US4501923A, filed September 13, 1982, and issued February 26, 1985.
  https://patents.google.com/patent/US4501923A/en?oq=US4501923.
  Patent.
• 
  “Adrenochrome.” PubChem.
  https://pubchem.ncbi.nlm.nih.gov/compound/5898.
  National Institutes of Health.